Method and apparatus for selectively viewing captioning

ABSTRACT

A method and apparatus for the selective display of motion picture subtitles. A liquid crystal display capable of forming alphanumeric images in one color on a background of a different color. The two colors are sufficiently similar so they are not able to be distinguished by the unaided eye of the viewer. A decoder, a microprocessor and a driver, for example, can be utilized to transfer coded information on standard motion picture film into appropriate subtitles which are then formed on a liquid crystal display. A color selective material is provided to a subclass of the viewers in the audience to enable the viewers in such subclass to distinguish the alphanumeric subtitles from the liquid crystal display background. This material could be provided in the form of glasses which extinguish either the alphanumeric images or the background, thereby either providing darkened letters on a light background or light letters on a darkened background. The subtitle projection and viewing apparatus and the method for its use can be utilized as a closed captioning system to permit the hearing impaired to view motion pictures in a mixed audience of hearing impaired and non hearing impaired individuals and view the dialog portion of the picture in subtitles while those individuals not wearing such wavelength selective glasses would not see the subtitles.

BACKGROUND OF THE INVENTION

[0001] It is estimated that throughout the world there are millions ofpeople that suffer some degree of hearing impairment ranging from mildloss to total deafness. Such conditions are attributed to genetics,accident, disease and environmental conditions including work related.

[0002] In order to accommodate the deaf and significantly hearingimpaired the motion picture industry has provided motion pictures withcaptioning which is the display of the audio text of the motion pictureprojected usually at the bottom of the screen.

[0003] Captioning has been well known in the motion picture industry anddates back to the days of silent movies and later the famous bouncingball sing along shorts. Captioning is also utilized in connection withmotion pictures to display a foreign language translation and to displayvarious captions as part and parcel of a motion picture. While captionsintegral with the projected image work well for delivering the audioportion of a motion picture to those who are not able to hear it, thereis a substantial reluctance of motion picture studios and exhibitors toprovide captions on regularly distributed pictures. The primary reasonis that it has been found that audiences without hearing impairment findsuch captions a distraction.

[0004] There have been a number of attempts to provide a caption of theaudio portion of a motion picture that cannot be seen by the hearingaudience and while some of them have provided this objective, they havenot been commercially accepted for various reasons.

[0005] U.S. Pat. No. 4,859,994 to Zola utilizes polarized eyeglasses ofthe type used in stereographic (3D) projection systems where each eyeviews a different projected image, However, the device disclosed in Zolarequires a 50 foot wide LCD (liquid crystal display) screen which wouldbe financially prohibitive to many smaller theater owners. It also wouldrequire the theater to be refitted with a polarization preservingscreen. U.S. Pat. No. 5,793,470 to Haseltine et. al. utilizes an LCDprojector to project a polarization encoded image onto a polarizationpreserving screen and viewing it with polarized glasses. There aresubstantial problems in reducing this method to commercial practicesince polarized filtered light has to be substantially brighter thanordinary projection levels due to the filtering.

[0006] The prior art also includes eyeglasses with individual textgenerators such as in U.S. Pat. Nos. 5,793,470 and 6,005,536 but atpresent such equipment would not be economical and the weight has foundto be uncomfortable to many users. There have also been prismaticglasses where the caption would be projected on the ceiling or rear wallof the theater and viewed with a prism or mirror arrangement. Thesesystems have not been well received since alignment is a problem andsome viewers have experienced headaches and eyestrain.

SUMMARY OF TILE INVENTION

[0007] It is the general aim of the present invention to provide a newand improved method and apparatus for displaying captions in conjunctionwith the exhibition of a motion picture whereby such captions are onlyseen by those desiring to see same.

[0008] In the present invention, use is made of closely spaced lightwavelengths that are indistinguishable to the naked eye whereby captionscan be viewed using a filter which only passes one of the twowavelengths. The viewing can be accomplished by special viewing glasseswhich would have lenses such as bifocals with the captioned part viewedthrough one portion and the main picture viewed through the other. It isalso possible to achieve the objects of the present invention utilizingsingular lenses.

BRIEF DESCRIPTION OF THE DRAWING

[0009] Additional objects and advantages of the invention will appearfrom the following description taken in conjunction with theaccompanying drawing in which:

[0010]FIG. 1 is a diagram of a selective caption viewing apparatusembodying the features of the present invention.

[0011] While the present invention is susceptible of variousmodifications and alternative constructions, illustrative embodimentsare shown in the drawings and will herein be described in detail. Itshould be understood however, that it is not to be intended to limit theinvention to the particular forms disclosed, but, on the contrary, theintention is to cover all modifications, equivalents, and alternativeconstruction falling within the spirit and scope of the invention asexpressed in the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0012] In the preferred embodiment monochromatic light at two closelyspaced wavelengths is utilized. The preferred source for such light islaser 10 with a first wavelength 10 a and laser 11 with a secondwavelength 11 a. Laser beam 10 b is vertically polarized and laser beam11 b is horizontally polarized. As shown in FIG. 1, the beams 10 b and11 b from said lasers, orthogonally polarized, are combined using apolarizing beam splitter 14. The resulting combined beam 15 whichcomprises beams 10 b and 11 b illuminate liquid crystal display 16 whichdoes not have a polarizer at its input face. While orthogonality of thepolarizations are essential, the choices of vertical and horizontalpolarizations were merely for the sake of convenience. The pixels of theLCD 16 that are on rotate the light by 90 degrees while the pixels thatare off do not change the polarization of the light. The light thenpasses through a polarizer 17 at the output face of the LCD 16 which isoriented to only pass vertically polarized light. Accordingly, offpixels transmit wavelength 10 a and the activated or on pixels transmitwavelength 11 a. A lens 18 images the two color liquid crystal displayonto the viewing screen 19. The wavelength difference between 10 a and11 a is small enough that the two colors cannot be distinguished by theunaided eye. The projected image is viewed by use of a wavelengthselective filter 20 which transmits only one of the two lightwavelengths in the image.

[0013] The permissible wavelength difference is smallest in theyellow-green part of the visible spectrum making the viewing apparatuscomplex. However, yellow-green light is the most visible which in turnminimizes the amount of light power required. Lasers meeting the withinrequirements are of the frequency-doubled diode-pumped solid state typeand are compact and adequately powerful but relatively expensive. Inorder to substantially reduce the cost of the lasers, an alternative isto use red light which allows a large wavelength difference and can beobtained relatively inexpensively but this advantage may be negatedsince low visibility in the red light range requires about 100 timesmore light power for adequate visibility.

[0014] As heretofore stated, to view the projected image on the screen19, a wavelength selective filter 20 is used which transmits onewavelength and attenuates the other. There are several types of filtersavailable which meet this requirement including absorptive filters,interference filters, and holographic notch filters. Absorptive filtersare generally the least expensive but are the least selective.Interference band-pass filters are available with adequate selectivity.Both absorptive and interference band-pass filters would more thanlikely be unsuitable for viewing the main projected image since most ofthe light would be

What we claim is:
 1. An apparatus for permitting the selective viewingof alphanumeric images comprising: first laser producing means emittinga beam with a first wavelength and polarized, second laser producingmeans emitting a beam with a second wavelength and polarized, saidwavelengths being close enough whereby the color difference cannot bedistinguished by the unaided eye, polarizing beam splitting means forcombining said first and second beams whereby they are combined andemitted in the same direction with orthogonal polarization orientation,liquid crystal display means for displaying a selected alphanumericimage having a first surface for receiving said combined beam and asecond surface for outputting said beam and provided with polarizingmeans whereby only vertically polarized light is passed, lens means forprojecting said light passed through said second surface on screenmeans, and viewing means comprising a wavelength selective filter whichtransmits only one of said wavelengths.
 2. The apparatus as set forth inclaim 1 wherein the polarization of said beam emitted from said firstlazer producing means is vertical.
 3. The apparatus as set forth inclaim 2 wherein the polarization of said beam emitted from said secondlazer producing means is horizontal.
 4. The apparatus set forth in claim1 wherein said laser producing means produce wavelengths in theyellow-green part of the visible spectrum.
 5. The apparatus set forth inclaim 1 wherein said wavelength selective filter is a holographic notchfilter.
 6. The apparatus set forth in claim 1 wherein said viewing meansinclude an eyeglass type frame.
 7. The apparatus set forth in claim 1further including third laser producing means emitting a beam with athird wavelength and vertically polarized with the wavelength of saidsecond wavelength being about halfway between said first and thirdwavelength and is combined with the beam from said first laser producingmeans by dichroic beam splitting means and then the combined first andthird beams are combined with the beam from said second laser producingmeans by said polarizing beam splitting means whereby the alphanumericimage is projected by the beams from said first and third laserproducing means and the background is projected by the beam from saidsecond laser producing means and the viewing means transmit only thebeams projecting said image.
 8. The apparatus set forth in claim 3further including third laser producing means emitting a beam with athird wavelength and vertically polarized with the wavelength of saidsecond wavelength being about halfway between said first and thirdwavelength and is combined with the beam from said first laser producingmeans by dichroic beam splitting means and then the combined first andthird beams are combined with the beam from said second laser producingmeans by said polarizing beam splitting means whereby the alphanumericimage is projected by the beams from said first and third laserproducing means and the background is projected by the beam from saidsecond laser producing means and the viewing means transmit only thebeams projecting said image.
 9. The method of projecting selectivelyviewable alphanumeric displays comprising the steps of providing a firstlaser beam with polarization, providing a second laser beam withpolarization with the wavelength difference between the color of saidfirst and second laser beam being small enough so as not to bedistinguishable by the unaided eye, providing a polarizing beam splitterto combine said first and second beams, passing said combined beamsthrough a liquid crystal display with input and output sides having theselected alphanumeric image inputted thereto, providing polarizing meansat the output side thereof, providing lens means for projecting theresulting image to project such image onto a selected surface andproviding viewing means comprising a wavelength selective filter whichonly transmits the wavelength projecting said image.
 10. The method asset forth in claim 9 wherein the polarization of said beam emitted fromsaid first lazer producing means is vertical.
 11. The method as setforth in claim 10 wherein the polarization of said beam emitted fromsaid second lazer producing means is horizontal.
 12. The method setforth in claim 9 wherein said laser producing means produce wavelengthsin the yellow-green part of the visible spectrum.
 13. The method setforth in claim 9 wherein said wavelength selective filter is aholographic notch filter.
 14. The method set forth in claim 9 whereinsaid viewing means include an eyeglass type frame.
 15. The method setforth in claim 9 further including the provision of third laserproducing means emitting a beam with a vertically polarized thirdwavelength with the wavelength of said second wavelength being abouthalfway between said first and third wavelengths and combining same withthe beam from said first laser producing means by dichroic beamsplitting means and then combining the combined first and third beamswith the beam from said second laser producing means by said polarizingbeam splitting means whereby the alphanumeric image is projected by thebeams from said first and third laser producing means and the backgroundis projected by the beam from said second laser producing means and saidviewing means only transmits those beams projecting said image.
 16. Themethod set forth in claim 11 further including the provision of thirdlaser producing means emitting a beam with a vertically polarized thirdwavelength with the wavelength of said second wavelength being abouthalfway between said first and third wavelengths and combining same withthe beam from said first laser producing means by dichroic beamsplitting means and then combining the combined first and third beamswith the beam from said second laser producing means by said polarizingbeam splitting means whereby the alphanumeric image is projected by thebeams from said first and third laser producing means and the backgroundis projected by the beam from said second laser producing means and saidviewing means only transmits those beams projecting said image.
 17. Themethod set forth in claim 9 wherein said viewing means transmits saidfirst and third wavelengths.